This project is concerned with the gathering of systematic information on psychophysiologic aspects of male and female sexuality. An approach to the study of psychophysiologic processes related to sexuality is the consideration of physiologic variations in genital organs and in gonadal hormones occurring during sleep. The overall objective is to obtain normative data on sex-related physiologic changes during sleep in males and females free of sexual problems with the aim of applying these findings to the study of patients with sexual disorders. Studies are proposed to obtain basic information on nocturnal penile tumescence and pituitary gonadal function during sleep in normal men. These data will provide a basis for similar studies to be conducted on men suffering from psychogenic impotency. In addition to increasing our overall knowledge of the subjects, the assessment of endocrine and penile tumescent changes in men with potency disorders may have diagnostic as well as prognostic significance. Studies concerning the psychophysiology of female sexuality will focus on the measurement of vaginal blood flow as an indicator of arousal in relation to electrophysiologic recording of sleep. As with men, it is expected that these findings may provide a basis for the systematic investigation of physiological changes in women with sexual disorders.